371. 两整数之和

为保证权益，题目请参考 371. 两整数之和(From LeetCode).

解决方案1

CPP

//
// Created by lenovo on 2020-09-30.
//

#include <iostream>

using namespace std;

class Solution {
public:
    int getSum(int a, int b) {
        unsigned ans = 0;
        unsigned add = 0;
        do {
            ans = unsigned (a) ^ unsigned (b);
            add = unsigned (a & b);
            a = ans;
            b = add << 1;
        } while (add != 0);
        return ans;
    }
};

void runTest() {
    Solution so;
    cout << so.getSum(1, 1) << endl;
}

int main() {
    runTest();
    return 0;
}

Python

# 371. 两整数之和
# https://leetcode-cn.com/problems/sum-of-two-integers/

################################################################################


class Solution:
    def getSum(self, a: int, b: int) -> int:

        MASK1 = 4294967296  # 2^32
        MASK2 = 2147483648  # 2^31
        MASK3 = 2147483647  # 2^31-1

        m = a
        n = b
        while n != 0:
            t = ((m&n) << 1) % MASK1
            m = (m^n) % MASK1
            n = t
        
        if m & MASK2:  # 负数
            return ~((m ^ MASK2) ^ MASK3)
        else:  # 正数
            return m


################################################################################

if __name__ == "__main__":
    solution = Solution()

    print(-2 & 1)
    print(-2 & 2)
    print(-2 & 4)